1. Field of the Invention
The present invention relates generally to video decoding, and in particular, to a multichannel video reception apparatus and method for digital broadcasting.
2. Description of the Related Art
In general, a digital broadcasting system, such as Digital Multimedia Broadcasting (DMB), simultaneously transmits the video data generated through coding/modulation/multiplexing processes over several service channels. A receiver receives desired video service data by demultiplexing a particular service channel. As there is an increasing demand for Quality-of-Service (QoS), and as the video technology has developed, the user can view video images of multiple channels (i.e., multichannel video images) on one screen of the receiver. Picture-in-Picture (PiP) is a typical example of the multichannel video images. PiP is useful when the user desires to view or scan other service programs with a smaller display screen while viewing a first selected service program with a larger display screen. The technology associated therewith includes an Electronic Program Guide (EPG) in which the user scans other service channels while receiving (or viewing) video data of a desired service channel on a screen.
In order to simultaneously decode video data received through more than two service channels in this way, there is a need for more than two video decoders.
FIG. 1 is a block diagram illustrating a multichannel video receiver with two video decoders according to the prior art.
As illustrated, a service channel primarily desired by the user is mapped to a main channel 100, and a service channel secondarily desired by the user is mapped to a sub-channel 110. In another case, a service channel desired by the user is mapped to the main channel 100, and a service channel the user desires to scan is mapped to the sub-channel 110. A received signal including video data of the main channel 100 is demultiplexed/demodulated by a channel receiver A 102, and then input to a video decoder A 104. The video decoder A 104 decodes the data output from the channel receiver A 102, and outputs a main-channel video signal 106. The main-channel video signal 106 is displayed on a screen after passing through a video buffer (not shown). Similarly, a received signal including video data of the sub-channel 110 is demultiplexed/demodulated by a channel receiver B 112, and then input to a video decoder B 114. The video decoder B 114 decodes the data output from the channel receiver B 112, and outputs a sub-channel video signal 116. The sub-channel video signal 116 is displayed on a screen after passing through a video buffer (not shown). The sub-channel video image can be down-sized according to its displaying size on the screen.
The use of two or multiple video decoders can maximize video decoding performance, but is not appropriate for a portable DMB receiver due to the high system complexity. In addition, the use of an additional decoder for the service requiring lower-resolution video processing for the sub-channel, like the PiP and EPG, unnecessarily increases the system complexity.